For example, PVC is a typical polymer that has been widely used for pipes for piping systems, food packaging materials, textile fibers, home decorations, blood storage containers, and infant articles such as nursing bottles, toys, etc. However, PVC has certain hardness due to the limit of its molecular mobility since a unique hierarchy structure and microcrystallite are present in the PVC, the microcrystallite playing a role in its physical crosslinks. Therefore, a flexible characteristic should be given to the PVC by means of a plasticization process in order to apply to flexible products such as food package films. A flexible PVC is generally manufactured by mixing a low molecular weight liquid plasticizer with PVC to form a plastisol, followed by heating the resultant plastisol to dissolve the PVC into the low molecular weight liquid plasticizer and cooling the plastisol. A phthalate plasticizer, a phosphate plasticizer, a trimellitate plasticizer, an aliphatic diester plasticizer, etc. has been widely known as the low molecular weight liquid plasticizer, and there are also an epoxy plasticizer, an anti-chlorine plasticizer, etc in addition to the above plasticizers. The flexibility is given to the PVC since its molecular mobility is significantly improved when a low molecular weight liquid plasticizer is added to the PVC.
As described above, the low molecular weight liquid plasticizer may very effectively used for softening PVC, but has characteristics that it is volatile in the air due to inherent characteristics of low molecular weight liquid materials, or it is transferred to the outside of the PVC when it is in contact with liquid or solid materials. It has been reported that the plasticizer migrated to the outside of the PVC is very harmful to the plants and the animals since it inhibits the normal activity of the endocrine system which is directly involved in their life activities or induces the abnormal activity of the endocrine system when the plasticizer is permeated into the bodies of plants and animals including human beings.
Accordingly, there have been continuous attempts to suppress the migration of a plasticizer.
For example, there have been attempts to substitute a low molecular weight liquid plasticizer with a high molecular weight plasticizer in order to solve the migration of plasticizers from PVC products. However, the problem is that, when the high molecular weight plasticizer is used in the PVC products, its economic efficiency is low or its plastic performance is not sufficient, and the chain entanglement appears in the high molecular weight plasticizer.
Meanwhile, it has been reported that cyclodextrin may contribute to suppressing the migration of plasticizers from flexible PVC since the cyclodextrin forms a complex with a low molecular weight liquid plasticizer such as DOP, as disclosed in Journal of Applied Polymer Science, 1996, Vol. 59, P. 2089 “Effect of blending β-cyclodextrin with poly (vinyl chloride) on the leaching of phthalate ester to hydrophilic medium”.
As shown in α-cyclodextrin of the following Formula 1, the cyclodextrin is a cyclic compound composed of glucose groups as a repeating unit, and represented by the following Formula 2.

wherein, “n” represents the number of the repeating units of glucose groups, and is an integer from 6 to 26, and preferably from 6 to 8.
The cyclodextrin has a unique structure composed of an outer part surrounded by hydrophilic hydroxy functional groups; and a hydrophobic cavity. The cyclodextrin may form a complex with a plasticizer having a suitable size for entering the cavity, namely a low molecular weight liquid plasticizer. In addition that the cyclodextrin derivatives attract the low molecular weight liquid plasticizer into their cavities, the cyclodextrin derivatives also attract and fix the low molecular weight liquid plasticizer by means of hydrogen bonds, etc.
However, if the cyclodextrin is mixed with the PVC and the low molecular weight liquid plasticizer, they cohere to each other due to low dispersibility, and therefore an effect on the suppression of the migration of the plasticizer is significantly poor, and physical properties of the manufactured flexible PVC are also deteriorated. In order to solve the problems, a flexible PVC with suppression of the migration of a plasticizer was manufactured using a method including steps of dispersing PVC, DOP and cyclodextrin in a dimethylacetamide (DMAc) solvent and casting the resultant mixture, as disclosed in the above literature. However, the method has also problems that its economic efficiency is low and it is difficult to mass-produce PVC products, as well as the cohesion of the cyclodextrin is not completely solved.